PARASITIC CASE OF THE WEEK
January 22, 2007

CASE #21

A 46-year-old white man in Texas developed bloody diarrhea. Flexible sigmoidoscopy revealed undermined ulcerations of the sigmoid colon. Slide #1268 shows a biopsy section of one of the ulcers. A scraping from one of the ulcers was stained and examined microscopically (#530).

Questions:
a. What is the diagnosis?
b. What are the characteristic features that are diagnostic in slide #530?
c. What organs other than the colon may be involved?
d. If the patient had present with gradually escalating fever and RUQ pain but no diarrhea, what would you have expected to find on sigmoidoscopy?

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ANSWERS TO LAST CASE:

CASE #12

A 30-plus-year-old Black African presented to the Emergency Room complaining of a moving vein in his scrotum. Physical examination was almost compatible with a diagnosis of a varicocele, Slide #826.

The correct diagnosis was established after minor surgery, Slide #827.

Questions:
a. Diagnosis please?
b. How is the infection acquired?
c. What is the most common presentation of this parasite?

ANSWERS:
a. Infection with Dracunculus medinensis.
b. Infection is initiated when an individual drinks water containing water fleas (for example Cyclops) which harbor infective larvae.
c. The parasite frequently presents at an ulcer near the ankle. If the ulcer is immersed in water, e.g. in a step well or watering hole, hundreds of larvae are released and eaten by Cyclops where they develop into infective forms.